futz,

I think your sister is being incredibly self-centered. Piling more guilt on you is not fair. It makes it difficult living with her when she's holding you hostage to keep her secrets. Seems to me her husband should be intervening in the stress seizures, migraines and drug use. What's his role in all this?

I think the root of her issues with you is really an unwillingness to focus on her own. Sounds like the family is aware that something is going on, too, without you saying a word. I don't think it is realistic to expect much understanding from her right now. In fact, it sounds like an intervention is coming from the rest of the family. If they are not offering you a place to live, be sure they know she says she'll kick you out if you have any part in it.

You are the stable one between the two of you. Be sure to take care of yourself first. Do you need a med adjustment for the hypomania?

Stay strong, futz.